Variation in hospital mortality rates with inpatient cancer surgery

Abstract

Objective: To elucidate clinical mechanisms underlying variation in hospital mortality after cancer surgery

Background: : Thousands of Americans die every year undergoing elective cancer surgery. Wide variation in hospital mortality rates suggest opportunities for improvement, but these efforts are limited by uncertainty about why some hospitals have poorer outcomes than others.

Methods: Using data from the 2006-2007 National Cancer Data Base, we ranked 1279 hospitals according to a composite measure of perioperative mortality after operations for bladder, esophagus, colon, lung, pancreas, and stomach cancers. We then conducted detailed medical record review of 5632 patients at 1 of 19 hospitals with low mortality rates (2.1%) or 30 hospitals with high mortality rates (9.1%). Hierarchical logistic regression analyses were used to compare risk-adjusted complication incidence and case-fatality rates among patients experiencing serious complications.

Results: The 7.0% absolute mortality difference between the 2 hospital groups could be attributed to higher mortality from surgical site, pulmonary, thromboembolic, and other complications. The overall incidence of complications was not different between hospital groups [21.2% vs 17.8%; adjusted odds ratio (OR) = 1.34, 95% confidence interval (CI): 0.93-1.94]. In contrast, case-fatality after complications was more than threefold higher at high mortality hospitals than at low mortality hospitals (25.9% vs 13.6%; adjusted OR = 3.23, 95% CI: 1.56-6.69).

Conclusions: Low mortality and high mortality hospitals are distinguished less by their complication rates than by how frequently patients die after a complication. Strategies for ensuring the timely recognition and effective management of postoperative complications will be essential in reducing mortality after cancer surgery.

Figure 1. Study design and enrollment schema

This study included 2708 patients at 19 low mortality hospitals and 2924 patients at 30 high mortality hospitals

Figure 2. Incidence of complications, case-fatality rates and odds-ratio of mortality in low and high mortality hospitals

Adjusted for race, gender, age, ASA class, functional status, dyspnea, ischemic heart disease, congestive heart failure, diabetes mellitus, albumin, creatinine, BMI, hematocrit, platelets, stage, emergency surgery, comorbidity and hospital rank. Odds ratios and 95% confidence intervals shown above the columns.